Acoustic element



July 28, 1931. s. B. SKLAR ACOUSTIC ELEMENT Filed June 26, 1928 jive/2E1 amul 73, 13% 3% W W;

Patented July 28, 1931 UNITED STATES PATENT OFFICE THOMAS S. HAMMOND,

OF CHICAGO, ILLINOIS ACOUSTIC ELEMENT Application filed June 26,

The invention relates to acoustic elements.

In oflices, apartments, auditoriums, and other places, it is frequently desired to dampen or absorb the sound originating outside of the room, and to improve the acoustic propertles of the room.

The primary object of the present invention is to provide a simple and efficient element by which this may be accomplished.

Another object of the invention is to provide an acoustic element of this character in the form of a panel or plate which may be conveniently and readily placed in any ortion of the room where it will be most efective to absorb the sound which is not desired in the room.

The invention consists in the several novel features hereinafter set forth and more particularly defined by claims at the conclusion 2o hereof.

In the drawings: Fig. 1 is a diagrammatic view showing an element embodying the invention hun on the wall'of-a room. Fig. 2

is a perspective of the acoustic element. Fig. 3 is a vertical section.

The invention is exemplified in an element comprising a plurality of superposed corrugated sheets 10, 11, 12, and 13, of corrugated strawboard which are stitched together by staples 14; a microphonic plate or circular disk 15 mounted in the front of the corrugated member 10, and a plate 16 interposed between the contiguous crests of the corrugations in the plates 10 and 11 to stiffen the element and 36 prevent the spreading of the corrugated portions of the members thereof. A circular o ening 17 is cut in the front face portions of the member 10 to receive and securely retain the plate 15. The latter is adaptedto 4 receive and collect the various sound vibrations or oscillations for transmission to the corrugated member 10.

The corrugated member 10 is treated to render it highly absorbent of sound. This treatment consists of mixing magnesium chloride and magnesium oxide and a small amount of (glue, gelatine, or other agglutinant, and a ding sufiicient water so that the mixture, when boiled, will form a colloidal material in the form of a thin paste. One

araniatic or oxycarboxylic with ten per cent 1928. Serial No. 288,495.

per cent by way of glue is sufficient for the purpose. The glue or colloidal material causes a marked foaming in boiling of the mixture. This thin paste is of the propel. consistency to coat'or saturate the member u which may be done by forcing it through perforated peripheries of corrugated rollers between which the paper-board is passed and squeezed, so that the compound will be distributed throughout and completely saturate all portions of the board. After the board has been thus treated, it will be dried, and the mixture will harden. This treatment has been found to produce a suflicientl porous product or member which will be highly ab- 5 sorbent. If desired, one or more of the corrugated members may be thus treated. The spaces or cells formed between the members also serve to deaden or dampen the sound. The back corrugated members form a non- 7o resonate backing for the absorbent front member 10. The microphonic plate 15 ma be formed of receiver-absorber com oun a such, for .example, as a mixture of ydro- '25 of acid and a small percentage of benzoic and anhydride.

The element is preferably made in the form of a panel which may be hung on the wall of the room or on an article of furniture or any so place where it will be most effective in absorbing sounds which are not desired. This panel 1s preferably placed where it will be exposed to receive sound. In a test it has been found that a panel approximately 9 x 12 will be efficient in absorblng the sound as desired in aroom about 12 x 20 In practice, it has been found that a panel of ordinary corrugated board treated with the compound as hereinbefore set forth and attached to a non-resonate backing will absorb the undesirable noises or sound in a room and gradually improve the acoustic properties in the room. Bein in the form of a panel, the element is a apted to be placed wherever it may be most efficient to attain the desired results. The panel may be produced at a low cost, so that any desired number of them may be advantageously used.

The invention is not to "be understood as restricted to the details set forth, since these may be modified within the scope of the appended claims, without departing from the spirit and scope of the inveniton.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. In an acoustic element, an exposed panel comprising a member which is treated with a compound to render it highly absorbent of sound, and a non-resonate member secured together.

2. In an acoustic element, an exposed panel comprising a member which is highly absorbent of sound and a non-resonate member secured together, and a microphonic plate on one of the faces of the absorbent member.

3. An acoustic element comprising a corrugated member treated with a compound to render it highly absorbent of sound.

4;. An acoustic element comprising a corrugated member treated with a compound to render it highly absorbent of sound and a non-resonate member'secured thereto.

5. An acoustic element comprising a corrugated member treated with a compound to render it highly absorbent of sound, and a microphonic plate on one of the faces of the absorbent member.

6. An acoustic element comprising a member which is highly absorbent of sound, a nonresonate member secured thereto, and a microphonic plate secured to an exposed face of the absorbent member.

7. An acoustic element comprising an exposed panel of corrugatedboard treated with a colloidal solution to render it highly absorbent of sound.

8. An acoustic element comprising a panel of corrugated board treated with a colloidal solution to render it highly absorbent of sound, and a non-resonate member secured thereto.

9. An acoustic element comprising a panel composed of a plurality of sheets of corrugated board secured together, one of which is treated with a colloidal solution to render it highly absorbent of sound.

10. An acoustic element comprising a panel comprising a sheet of corrugated hoard treated with a colloidal solution to render it highly absorbent of sound, a non-resonate corrugated panel secured thereto, and a microphonic plate secured to an exposed face of the treated panel.

Signed at Chicago, Illinois, this 19th day of April, 1928.

SAMUEL B. SKLAR. 

